Interlocking system for railroads



PATENTED SEPT. 20, 1904.

B. C. HOWELL. INTERLOGKING SYSTEM FOR RAILBOADS.

APPLICATION FILED JAN. 9, 1902.

2 SHEETS-SHEET 1.

NO MODEL.

(- |l|||||||||||||||| Elllllllllllllllll' PATENTED SEPT. 20, 1904.

B. 0. ROWELL. k INTERLOGKING SYSTEM FOR RAILROADS.

APPLICATION FILED JAN. 9, 1902.

2 SHEBT8-SHBBT 2.

N0 MODEL.

UNITED STATES Patented September 20, 1904.

PATENT OEEicE.

BENTON O. HOWELL, OF CHICAGO, ILLINOIS, ASSIGNOR TO ROWELL POTTER SAFETYSTOP COMPANY, OF PORTLAND, MAINE, A COR- PORATION OF MAINE.

INTERLOCKING SYSTEM I 'OR RAILROADS.

SPECIFICATION forming part of Letters latent No. 770,656, datedSeptember 20, 1904.

Application filed January 9, 1902. Serial No. 89,006. (No model.)

To all whom it may concern:

Be it known that I, BENTON O. RowELL, of Chicago, in the county of Cookand State of Illinois, have invented a new and useful InterlockingSystem for Railroads, of which the following is a specification,reference being had to the accompanying drawings, making part hereof.

Interlocking systems as now used comprise an interlocking machine, whichconsists of a series of levers for clearing or blocking the tracks andmechanical locking devices, such that when one or more levers have beenreversedthat is, moved from normal far enough to shift certain of theblocking appliances from danger to safety and clear a certain route-alllevers which control conflicting routes are mechanically locked and allconflicting levers remain mechanically locked while any one of them isreversed. The result is that when any train approaching a crossing callsfor signals giving it the right of way the operator at the interlockingmachine sets up a route for that train by reversing the proper lever orlevers, and thereby shifting the proper appliances to safety.

Usually visible signals which inform the engineer whether his route isclear or not are used as blocking appliances and in addition prohibitorysignals which derail or otherwise stop any train attempting to pass indisregard of the visible signal when at danger. The train which calledfor signals then passes over the crossing, and all conflicting trainsare prohibited from so doing; but should a conflicting train call forsignals before the first train had cleared the crossing and should theoperator forget himself he would restore the lever he had reversed, (togive right of way to the first train,) and thereby shift the prohibitorysignals in front of or under the first train and take away the right ofway from that train to which he had just given the right of way. Toprevent this, it has long been usual to provide an electrical lock,which makes it impossible for the operator of the interlocking machineto restore a lever he has reversed to give right of way to a train whilethat train is on the crossing, and interlocking systems forrailway-crossings have long been known in which each train must firstcall for signals, the operator must next reverse the proper lever orlevers to clear a route for that train over the crossing, and therebymechanically look all conflicting levers, and, thirdly, that train inpassing over the crossing automatically made or broke an electriccircuit which operated a locking device or devices and prevented theoperator of the interlocking machine from restoring the lever he hadjust reversed to normal while that train was on the crossing, andthereby prevented the operator from reversing any lever controllingconflicting routes. In short, the interlocking machine prevented theoperator from clearing two conflicting routes by the mechanicalinterlocking of its levers, except when the operator forgot himself andattempted to restore the lever he had reversed to clear one route whilethe train was passing over that route and the passing trainautomatically prevented the operator from restoring that lever while thetrain occupied that route. Heretofore in these systems the train tookcontrol of the interlocking machine away from the operator when itsfront wheels entered the section of track over which it had obtainedright of way from the operator of the interlocking machine and retainedthat control until its rear wheels had left that section of track, whenit surrendered control of the interlocking machine to the operator, andthis is highly objectionable, as it causes a train to hold control ofthe section longer than is practical at busy crossings, and the onlymeans heretofore known for shortening the time during which the passingtrain held control of a section was to reduce the length of thatsection, and thereby make the protection questionable.

My invention is subdividing the section into three sections andproviding means whereby the entrance of a train on either of the eX-treme sections takes away the control of the lever for operating theblocking appliances from the operator and causes the train to retainthat control until the rear wheels of the train leave the middle sectionand to surrender that control when the rear wheels of the train leavethe. middle ection, also a novel electric locking device for a lever ofan interlocking machine, and also a novel electric switch operated byeither of two levers, so disposed that the first lever operated takescontrol of the electric switch and also inhibits the second lever fromcontrolling that switch that is, the passing train automaticallyoperates the levers successivelyand the operation of either lever firstnot only gives control of the switch to that lever, but also causes thelever first operated to prevent the action of the other lever on theswitch.

In the drawings, Figure 1 isadiag-ram illustrating one embodiment of myinvention. Fig. 2 is a front view, and Fig. 3 an edge view, of thepreferred form of circuit-controlling device. Figs. 4 and 5 show theelectromechanical lock for the interlocking machine.

In Fig. 1 I show two tracks R R and blocking appliances S to S normallyat dan ger, so that no train can pass over either track until it hascalled for signals and until the operator at the interlocking machine(indicated by L) has replied to the call by setting up the route calledfor, which he does by reversing the proper lever or levers of theinterlocking machine, long used and too well known to need descriptionexcept as to my electromechanical locking device, which constitutes onefeature of my present invention.

The interlocking machine is shown as having two levers, and the lever Lmust be reversed to clear the route over track R and locks the otherlevers in the well-known way. So reversing-lever L clears R and locksthe other levers. In short, only one of these two levers can be reversedat one time, and of these two levers one will be locked in its normalposition when the other is reversed, so that when one is reversed itmust be restored to its normal position before the other one can bereversed. This is the familiar mechanism for interlocking long wellknown and familiar to all skilled in this art. One example of such aninterlocking machine is fully described in Patent No. 7 24,947 datedApril 7, 1903.

When both levers L L are normal, all the routes are blocked; but eithercan be unlocked by reversing its controlling-lever, and when theoperator hears a call for signals over either route he reverses thecontrolling-lever of that route and sets up or clears that route; butshould he hear a call for signals over a conflicting route he must firstrestore the lever of the cleared route before he can reverse the leverof a conflicting route, and therefore I have provided theelectromechanical lock. (Shown in Figs. 4 and 5.) This lock consists,

as shown, of a slide 79, notched for lockingbolt p,which is actuated bymagnet P through armature p and lever 13 which carries locking-bolt 12.There are two of these slides 39, one for each lever, and when eitherlever is reversed the notch of its slide 19 is carried under its bolt p,and that bolt drops into that notch, the magnet P being then notenergized; but when magnet P is energized its armature p is attracted,lever 10 raised, and bolt 19 withdrawn from its notch in slide p, andthe lever which actuates slide 19 can then be restored to its normalposition.

When both levers L L of the interlocking machine are at normal, neitheris locked and either can be reversed, but all routes are blocked, andreversing either lever locks the other in normal position, and the leverreversed is also locked in its reversed position by its slide p and bolt19 and the proper route is cleared, leaving the other route blocked andlocked. Moreover, the lock of the reversed lever is under control ofmagnet P, so that the reversed lever cannot be restored until a currentis sent through the coils of magnet P.

If there be no train on either route and one of the levers be reversed,the operator can send a current through magnet P of the reversed leverto lift boltwp, so that he may restore the reversed lever; but if therebe a train on the route controlled by that reverse lever the circuit(which is formed in part by the coils of the magnetP of that route) isbroken and remains broken until the rear wheels of a train on that routehave traveled over the crossing far enough to prevent all possibility"of its being struck by a train over a conflicting route. For example,suppose a train on track R calls for signals, all the routes being thenblocked. The operator then sets up the route on R by first reversing itslever L, and thereby locks lever L in the usual way and also looks leverL in its reversed position by the slide 9 and bolt Should a train on Rcall for signals before the train on R has passed the crossing andshould the operator forget himself or erroneously suppose that the trainon R had passed and try to restore the lever of R preparatory to settingup the route over R the slide 9 and bolt 1) of the lever L of R preventhim from restoring lever L, and he cannot remove bolt p from slide p oflever L of R by sending current through the circuit of magnet P of thelever L, for the reason that that circuit is automatically broken atswitch (1 g by the presence of a train on route R. This will be plainfrom Figs..2 and 3, taken with Fig. 1. In Figs. 2 and 3 the electrodes gg of the switch are moved into and out of contact by lever Q. So long asboth magnets A and B are energized (1 and Q3 are in contact; but whenmagnet B is short-circuited by the entrance of a train on section m oftrack R its armatureb is thrown out by spring'b and swings lever Q,carrying electrode g away from electrode 9 The break at g Q3 isautomatically caused by the entrance of a train on section m of R andremains, of course, until the rear wheels of that train have leftsection 03 of R; but as soon as the front wheels of that train pass fromsection 00 to section m of R that is, pass derailer S for S S &c.,indicate derailers or the likemagnet D is short-circuited and thecircuit of magnet B automatically broken at 6 5 so that a train passingover R from the right automatically breaks the circuit of magnet B, andthe operator cannot close that circuit until the rear wheels of thattrain have left section m of R, and a train passing over section 00 of Rfrom right to left acquires control of magnet P and takes away controlof magnet P from the operator as soon as its front wheels enter section00 of R at the right and keeps control of magnet P until its rear wheelsleave section m of R at the left, when the operator reacquires fullcontrol of magnet P through his switch q q.

The break at 72 6 remains until the rear wheels of the train have leftsection 00 of track R and have also passed signal S, (which is, in fact,a derail and cannot be passed except when at safety;) but as the rearwheels of the train leave section m near S, current flows through magnetD, which attracts its armature and closes the circuit of magnet B at 6 6when current flows through circuit of magnet B, which attracts itsarmature and closes circuit of magnet P at g (1 When the circuit throughlocking-magnet p is closed vat (1 Q3, that circuit is complete except atthe operators switch Q q, so that the operator can then unlock thereversed lever L by making contact at q q, and this is done in practiceby a switch always under control of the operator, but normally with itspoints (1 q separated. It will also be plain that when the front wheelsof the train leave in at S and enter 00 and short-circuit magnet D thefall of the armature D not only-breaks the circuit of magnet B at b 5but also of magnet A at a a andmagnet A drops the armature (1- onto theend of armature b of magnet B, but without affecting lever Q, or switchQ2 Q3, then under control of armature b. This provision of a break at aa when a train from m enters 00 is precautionary merely, for when thefront wheels of a train pass from section 00 onto section :0 of R magnetA is short-circuited and its armature a would drop if there were nomeans for dropping it before; but armature (4 cannot drop far enough tostrike lever Q, as armature Z) is then in the way, so that armature a isupheld by armature b. Magnet A remains short-circuited until the rearwheels of the train leave section if; but as soon as the rear wheels ofthat train leave section of magnet D ceases to be short-circuited, becomes energized, attracts its armature d, and closes the circuit ofmagnet B at b 6 also of magnet A at a a and magnet B becomesreenergized, attracts its armature b,

which is moved far enough to allow lever Q, to close the circuit ofmagnet P at (7 (1 but armature b is stopped by its shoulder 6* engagingarmature a, so that armature bcannot be fully retracted until armature ais lifted, which happens when the rear wheels of the train leave section00 when both armatures a and 6 return to normal, both magnets A and Bbeing then energized.

It will now be plain that locking-magnet P is not under the control ofthe operator from the moment when the front wheels of a train movingfrom right to left enter section :11 until the rear wheels of that trainleave section 00 at S and from the moment when the front wheels of atrain moving from left to right enter section 00 until the rear wheelsof that train leave section 00 at S For a train running from left toright over R, as soon as its front wheels enter section w short-circuitsmagnet A, and thereby drops armature a, which moves lever Q to break thecircuit of magnet P at 9 and as soon as its front wheels enter sectionshort-circuits magnet D and drops armature (Z, breaking the circuit ofmagnet A at a a, and incidentally of magnet B at 6 b and as soon as itsrear wheels leax e section at S magnet A is no longer short-circuited,but the circuit is broken at a a and as soon as its rear wheels leavesection 00 at S magnet D is no longer short-circuited, but isreenergized, and the break at (0 in the circuit of magnetA is closed andmagnet A is reenergized, its armature a moving far enough to close thebreak at g g in the locking-circuit through the coils of magnet P, butnot making the whole of its return stroke, for the reason that as soonas magnet D drops its armature the circuit of magnet B is broken at b band its armature b thrown by spring 6 onto armature a, so that whenmagnet A is reenergized (by the rear wheels leaving section 00 theshoulder a of the armature a engages shoulder 7) of armature b, and bothare thus interlocked until the rear wheels of the train running fromleft to right have left section :10. Of course when the front wheels ofa train running from left to right leave section :0 and enter section 00the battery of magnet B is short-circuited, and magnet B would then dropits armature circuit had not before been broken at The operation of atrain running over R in either direction and its automatic control oflocking-magnet P through magnets A B and D will be plain without furtherdescription.

The main object of my invention, as will now be clear, is to keep themain levers of the interlocking machine when reversed under control ofthe passing train until the rear wheels of that train have left section00 of R or of R and then taken away that control from the passing trainand restore it to the operator at the interlocking machine, my mainadvance in the art being that heretofore the passing train retained thatcontrol until its rear wheels left section 00 if running from right toleft, or its rear wheels left section 00', if running from left toright. It will also be obvious that my invention is not limited tocrossing railroad tracksas, for example, track R as opposed to R mightbe a highway or a drawbridge or, in short, any other obstacle to thefree running of a train over R, and vice versa.

The gist of the matter is that a train from any direction automaticallytakes control of the'interlocking machine after the operator has set upthe route and retains that control until the rear wheels of the trainhave left the middle one of these sections.

While I have shown the levers for controlling-switch g Q3 as armatures aand b ofmagnets, it is obvious that these levers may be successivelyoperated by other means than electrical or magnetic, as will be plainwithout description.

What I claim as my invention is 1. The interlocking system abovedescribed com prising a railway-track divided into three insulatedsections, blocking appliances for said track under control of a leverwhich when in one position clears that track 'for the passage of trainsand which when in the other position blocks that track; a locking-boltlocking that lever when in position for clearing the track; means bywhich the operator can shift the locking-bolt and control the lever whenno train is on the track; and automatic means by which the entrance of atrain on either extreme section takes away the control of thelocking-bolt from the operator, retains that control while the traintravels over one extreme section and the intermediate section, andsurrenders that control to the operator when the train leaves theintermediate section.

2. In an interlocking system in combination with a lever; alocking-slide carried by that lever; a bolt locking that slide when itslever is reversed; an electromagnet for disengaging the bolt from theslide; and means for energizing that magnet under the joint control ofthe operator and a passing train.

3. In combination an electric switch whose points (1 g are controlled bya lever Q; levers a and I), either one of which will when swung on itsfulcrum operate lever Q; means for swinging each lever 64 and b, on itsfulcrum; and means carried by the levers a and b, by which lever anautomatically prevents the back swing of levers 6 and Q, when levert hascontrol of lever Q, and lever & automatically prevents the back swing oflevers a and Q when lever 60 has control of lever Q.

BENTON O. HOWELL.

Witnesses:

CHAs. J. DE BERARD, B. FRANK HATHAWAY.

